Where are the productivity gains in government? Consider a core function of state and local governments: schools. Over the period 1970-2005, school spending per pupil, adjusted for inflation, doubled, while standardized achievement test scores were flat. Over roughly that same time period, public-school employment doubled per student, according to a study by researchers at the University of Washington. That is what economists call negative productivity.

But education is an industry where we measure performance backwards: We gauge school performance not by outputs, but by inputs. If quality falls, we say we didn't pay teachers enough or we need smaller class sizes or newer schools. If education had undergone the same productivity revolution that manufacturing has, we would have half as many educators, smaller school budgets, and higher graduation rates and test scores.